New AD concerns Lycoming connecting rods
The FAA issued an airworthiness directive focusing on certain connecting rod assemblies installed in a range of Lycoming engines. It is the kind of announcement that likely has pilots leafing through their engine logs to find the date of their last overhaul and determine exactly which parts were replaced.
The agency said the AD, which affects an estimated 16,000 engines, “was prompted by several reports of connecting rod failures resulting in uncontained engine failure and in-flight shutdowns.” The directive includes a diversity of engine types including carbureted, fuel-injected, geared, aerobatic, and helicopter models with displacements from 233 to 580 cubic inches.
Compliance with the AD requires visual inspection for bronze particles in the oil filter, oil pressure screen, and oil suction screen, depending on engine configuration. Such particles are a sign of excessive wear of the small end connecting rod bushings.
The inspection is to take place during the next oil change or within four months of the AD’s effective date—whichever happens first—and at every subsequent oil change until the bushings are replaced. Aircraft owners holding at least a private pilot certificate can perform the inspections, which must be entered into the aircraft’s logs. The FAA estimated the costs of complying with the AD at $12.19 million for bushing replacements, $3.76 million for oil inspections, and $1.36 million for bushing inspections.
In 2017 the FAA issued an emergency AD requiring inspection and possible replacement of Lycoming small end bushings installed between November 2015 and February 2017.
